Growing Healthy Soil: Healthy Soil 1

3/14/18 Today’s Class Growing Growing Healthy Soil: Healthy Soil 1. Soil physical properties: texture and structure 2. Improving physical & biological properties with organic matter 2018 3. Soil chemistry: pH and nutrients Extension Gardener Short Course 4. Soil testing Class 2 What do healthy soils provide plants? • Water & Nutrients + • Want right amount and Healthy soil is the foundation of healthy constant supply of plant growth both + • How do plants get water and nutrients from soils? Soil controls fate of water and nutrients ROOTS! What do healthy soils provide plants? • Water and Nutrients • Air! Roots have to have it! • Soils that are easy to dig have plenty of air • Microbes • Beneficial microbes help roots absorb nutrients and suppress soil diseases Root health and plant growth is directly • Microbes need water, nutrients and air reliant on soil conditions 1 3/14/18 What do healthy soils provide plants? Top growth directly proportional to root growth! Space/Depth • Roots need space to grow both deep and wide • Roots grow where there is air, water and nutrients • Want these to extend deep into the soil profile – ideally: – At least 8” for turf, annuals and vegetables – At least 2’ for shrubs and small trees – 3’ or more for large trees Soil Physical Soil Particles Properties Sand Improve before you plant! • Feels gritty, largest particle size • Particles • Cannot hold nutrients • Color Silt • Texture • Feels floury, medium particle size • Structure • Pure silt rare • Pores Clay • Compaction • Feels smooth, can mold, “ribbons” • Depth • Smallest particle size, holds Clay soils “ribbon” nutrients well You can’t fix it with fertilizer!!! when mashed Soil Color Red-orange • Due to Iron oxidation • Indicates good internal drainage Pale yellow, light gray • Poorly drained Darker colors, brown/gray hues • Organic matter darkens soils • Humus – what’s left when O.M. completely decomposed Top = rust Bottom = humus 2 3/14/18 Mottled Soil Soil Texture Mottled grey and orange or yellow • Relative results from amounts of sand, seasonally high silt and clay in soil water table • Mixture of 2 or Orange due to more = loam oxidized iron • Unrealistic to (rust) – Iron change soil cannot oxidize if texture low oxygen Piedmont Clay Implications of Texture • Water infiltration • Water holding capacity • Drainage • Aeration • Workability Ultimate product of continuous weathering of minerals in a humid, temperate climate Coastal Plain Soils Never work/dig wet clay! TOO WET! Smearing/Glazing 3 3/14/18 Coastal Plain Soils Drainage • Infiltration = surface drainage into the soil • Percolation = internal drainage through the soil profile Color as an indicator of drainage. The soil on the left is the Cecil series, a well-drained mineral soil typical of the NC piedmont. The soil on the right is the Coxville series, a mineral soil found in the NC coastal plain. Where is water coming from? If excess, can it be re-directed? Measuring Drainage – Dig 12” hole – Fill with water – Measure how long takes water to drain away • Less than an hour = excessive drainage • Less than 12 hours = good drainage • Over 24 hours = poor drainage Soil Depth Shallow Soils • Poor growth • Want good rooting environment to extend deep into soil profile – Due to shallow root systems – growth of plant above ground • Enables drainage and deep root growth directly proportionate to size of root system • Healthy soils = 12”+ deep • Uprooting in wind • Common problems: – Trees with shallow root • Compaction systems are much more likely • Rock to uproot in high winds – If soils less than 3’ deep do not • High water table plant large maturing trees • Low pH, low air content (over 30’) 4 3/14/18 High Water Table Assessing Soil • Water table found within 12” of soil surface in some areas Depth • Highest in late winter/spring • Roots cannot grow into Dig a hole! • Dig until you reach water, saturated soil (no air) rock, compacted layer, or • If seasonal high water table get tired! (spring only), roots grow deeper in summer and fall and are killed back each winter/spring Perched Water Table Perched Water Table • Occurs when soil layers of two different textures meet • Water will not freely move from one texture to another until first layer becomes Water saturated saturated top layer before moving into lower layer of different texture Adding gravel to containers does not increase drainage! Make Your Bed! • When amending soils, amend at least 10 sq. ft. area rather than planting hole • NEVER layer soils! Source: https://secure.clematisqueen.com/content/do-not-add-gravel- your-containers Amend whole bed, not just planting hole! 5 3/14/18 Depth Raised Beds • Cultivate deep • Into clay • Mix in aged organic matter/compost • Build up Trex – recycled plastic $$ • Above existing soil level • Ideally at least 12”, deeper for trees • Raised beds or berms • Fill with soil/compost mix • Don’t plant large maturing Treated or Concrete blocks trees (over 30’) in shallow untreated soils boards Soil Pores Soil Structure Water • Grouping of individual particles into clumps, aka aggregates • Creates pores • Allows water to move through soil and provides space for air Compare Large Pores • Hold air • Let water into soil, allow drainage Small Pores • Light • Heavy • More air space • Hold water Ideal Volume: • Dense – less air • Readily absorbs • Water available to plants 20-30% large pores • Slowly absorbs water water 20-30% small pores • Holds water • Drains water 6 3/14/18 The Problem with Clay: Compare Compaction Which is your soil more like? • Tiny particles – easily compacted • All small particles – hold water • Lack of large particles – low infiltration, drainage impeded Every yard was a construction site at Compaction some point in the past! • If it is difficult for you to dig, it is difficult for roots to grow! • Causes: heavy equipment, constant foot traffic • Compaction causes poor surface drainage – encourages growth of moss, as do shade and acid soil Moss is a symptom of compaction Compaction Symptoms: Lichen 7 3/14/18 Surface Rooting Root Rot, Poor Growth Turf fails to establish, Roots grow where there is air, low vigor Leyland cypress that died water and nutrients! from drowning Turning a Brick Factors Affecting into a Sponge Structure • Unrealistic to change • Wetting and drying texture = never add • Freezing and thawing sand!!! • Physical activity of roots • Want to improve structure • Animals • Organic matter binds soil • Soil tillage particles into aggregates = • Decaying organic matter improves structure A pickaxe is NOT a planting tool! Earthworms improve soil structure over time Organic Matter Increase Good Microbes • Improves number and distribution of large and small pores Microscopic organisms • Increases infiltration bacteria, fungi, nematodes • Improves drainage Help plants grow better • Increases water holding capacity = Suppress diseases one of best defenses against Thrive where plants thrive, in soils drought! that are • Also increases nutrient holding Consistently moist, not too wet capacity, adds nutrients and supports Rich in nutrients with moderate pH beneficial microbes! Have lots of organic matter 8 3/14/18 Organic Matter & Compost • Available to buy – In bulk from mulch dealers In bags from garden centers • No need to seek out special types (eg. Mushroom compost) Compost is available from most places that sell mulch. Compost: Organic Matter Make Your Own üGround pine bark – sold as pine or pine bark soil conditioner • A great way to recycle yard ü Rotted leaves (leaf mold) – debris and vegetable scraps! pile them up and let them rot 2-3 • Two methods: years • Active = turn regularly ü Aged manure – at least 6 (at least 1/week), ready months in 2-3 months X Peat moss – only holds water, no nutrients, only recommended • Passive = pile up and for extremely sandy soils let nature do the work, ready in 2-3 years Don’t waste your money! Will not fix your problems!!! Composting Composting – YES: Vegetable scraps, fruit peels, eggshells, lawn clippings, yard debris, leaves, straw, manure – NO: meat/scraps, pet waste, perennial Bins are weeds/weed seed, helpful diseased plants but not – Finished product is Some wood ashes okay but required! typically 1/3 original too much raises pH – volume! sprinkle thin layers 9 3/14/18 What about Topsoil? Incorporate! • The soil on top - No standards • Organic matter breaks • Often contains weed seed and down quickly in warm, roots – screening can remove some of these humid climates • May contain disease spores, • Till into soil each year insects, chemical residues • A couple of inches of topsoil • 2”-3” layer, mix in 6”-8” deep does not provide adequate – NOT sand, peat moss, rooting depth! vermiculite or potting soil! • Creates perched water table – Gypsum/Landplaster, aka “Clay • Not the answer to soil Buster” does not help! problems! Grow Your Own Compost! Seeding Cover Crops Cover Crops – Are mown or sprayed • Till soil and rake level when mature and left • Scatter seed thickly on soil surface over soil surface Green Manures • Rake in lightly – Are turned into the soil • Water Both are seeded directly into open garden spaces Cover Crops Cover Crops and Green Manures • Warm season cover crops: • Till in, mow, or spray a week or two – Sow mid-April – early Aug. after flowering begins – Cowpeas, soybeans, crowder peas = legume - add nitrogen • If leave too long, will set seed – Buckwheat = very quick, turn under in • When mowing – resprouting can 30-45 days be a problem • Cool season cover crops: • Can spray with glyphosate

Load more